닮다 is resembling somebody. It almost always shows up in the past form 닮았다 even about a present likeness, so 이렇게 닮았네 means 'they look so alike', not 'they used to'. The -게 slot gives the degree or manner: 이렇게 (this much alike), 묘하게 (oddly alike), 비슷하게 (similarly).